Clinical research, much of it sponsored by NIAID, has markedly improved survival of patients with HIV/AIDS. However, the epidemic continues to grow both in both developed and the developing world. In the U.S., minority groups, especially African-Americans, are disproportionately affected throughout the country. Nationally, African-Americans make up 40% of AIDS cases but only 12.3% of the U.S. population. This disparity is even greater among children and adolescents (ages 13 to 19 years), among whom African Americans make up 60% of AIDS cases but only 15% of the U.S. population. In Memphis, approximately 46% of the population is African-Americans but 90% of the HIV and AIDS cases occur n African-Americans. In addition, data from the CDC show that cumulatively, 36% of all reported AIDS cases have been in the South, but the South accounted for 45% of new AIDS cases in 2003. These data confirm the disproportionate growth of the epidemic in this region. Because of the evolving epidemiology of HIV infection in the U.S., Memphis is an ideal location for a domestic HIV/AIDS Clinical Trial Unit (CTU). Memphis is a large Southern urban area that provides tertiary health care for individuals in an approximately 200-mile radius in the states of Tennessee, Mississippi, Missouri, and Arkansas. This area has been identified as one of the poorest in the nation. Here, the proposed CTU, located at: St. Jude Children's Research Hospital, will provide clinical trial access for to underrepresented populations that are most severely affected by the epidemic;, including women, adolescents, and African-Americans. The proposed CTU is currently a Pediatric AIDS Clinical Trials Group Unit and is affiliated with the International Maternal Pediatric Adolescent Clinical Trials (IMPAACT) Group. The unit will have a single site located at St. Jude with a consortium agreement with the University of Tennessee Health Science Center. The unit will address all four scientific aims of IMPAACT: Prevention of Maternal to Child Transmission of HIV;Translational Research/Drug Development;Optimization of Clinical Management including Co- Morbidities;and Vaccine Research and Development. Based on the availability of severely affected populations, the experienced staff, and the strong history of clinical trial conduct and scientific contributions to the PACTG, the St Jude CTU will be a valued domestic unit for IMPAACT. ADMINISTRATIVE COMPONENT: